1. Field of the Invention
This invention relates to an automatic rubber control device for ships and more especially for sailing ships.
2. Description of the Prior Art
On known automatic control devices, a feeler means is in most cases a wind vane which is rotatably fitted to the stern of the ship and is connected, via a regulating means in the form of a transfer rod linkage, to an auxiliary rudder which is fitted to the transom of the ship and is specially adapted to the automatic control device. The length of the individual lever members in the transfer rod linkage is adjustable, so that the auxiliary rudder can be aligned parallel to the longitudinal direction of the ship in every position of the wind vane. In this way, it is possible to set the required position of the wind vane and consequently the required course of the ship.
If the actual course of the ship differs from the required course, the position of the wind vane, which is directed by the apparent wind (actual wind plus the wind caused by the speed of the ship), is changed relative to the ship. This causes the auxiliary rudder to be positioned in such a way that the ship returns to its required course. The influences causing the ship to go off course are very varied due; for example, to waves acting on the ship' hull, a varying tendency of a sailing ship to carry a lee or weather helm, depending on the force of the wind and the rigging, etc.
In the case of known automatic control devices which are constructed as described above, the force for actually actuating the auxiliary rudder has been applied by the wind vane. The latter is therefore a large, bulky unit which has to be attached to the ship in a suitably firm manner and requires a certain minimum wind force in order to be effective. The auxiliary rudder must also be very rugged and must be securely mounted on the transom, so as to ensure that the automatic control device will continue to operate reliably even in rough seas. All in all, the described automatic control devices are thus bulky in design, relatively expensive and necessitate elaborate measures for their secure fastening to the ship.
Another known automatic control device comprises as the regulating unit one or several electric motors which are controlled from the wind vane and actuate the rudder. Although such an automatic control system does not require an additional auxiliary rudder, it has the serious disadvantage that it necessitates an efficient power source which is very rarely provided on board, particularly on board a sailing ship, and which, if provided, can be relied on to a limited extent only.